The purpose of this project is to investigate the molecular structure of fibrous proteins and proteoglycans, and to study intracellular gelation of Hemoglobin S. The structural information obtained will be correlated with function. Areas of present interest are 1) Molecular structure and dynamics of collagen. Carbon-13 and deuterium magnetic resonance techniques are being used to study the structure and interactions in collagen fibers. 2) Proteoglycan dynamics. Carbon-13 magnetic resonance is also being used to study the molecular mobility of the polysaccharide and protein chains in cartilage proteoglycans. 3) Carbon-13 magnetic resonance is being used to study the extent and mechanism of hemoglobin S gelation in erythrocytes. For these studies, magnetic resonance spectrometers have been assembled which give multinuclear spectra of solids. High power decoupling, crosspolarization, magic angle spinning, and solid echo experiments are all performed.